Directional coupler for individually connecting each of plural inputs, without cross talk, to all of plural outputs

Claim 1

A DIRECTIONAL COUPLER FOR OPERATION WITH WAVES OF SPECIFIED FREQUENCY AND HAVING A SET OF M INPUT PORTS AND A SET OF M OUTPUT PORTS ADAPTED FOR COUPLING TO EXTERNAL TRANSMISSION LINES OF PREDETERMINED CHARACTERISTIC ADMITTANCE COMPRISING A PLURALITY (M) OF ELECTRICALLY PARALLEL TRANSMISSION LINES EACH INTERCONNECTING AN INPUT PORT TO A CORRESPONDING OUTPUT PORT AND HAVING EQUAL ELECTRICAL LENGTHS OF ODD INTEGRAL QUARTER WAVELENGTHS; A FIRST STAR CONNECTION INTERCONNECTING EACH OF SAID TRANSMISSION LINES AT ONE END AND A SECOND STAR CONNECTION INTERCONNECTING EACH OF SAID TRANSMISSION LINES AT THE OTHER END, THE BRANCHES OF SAID STAR CONNECTIONS HAVING AN ELECTRICAL LENGTH OF AN ODD INTEGRAL EIGHTH WAVELENGTH; SAID TRANSMISSION LINES AND SAID BRANCHES HAVING CHARACTERISTIC ADMITTANCES CHOSEN SO THAT THE INPUT SET OF PORTS IS MATCHED WHEN THE OUTPUT SET IS PROPERLY TERMINATED BY CONNECTION TO AN EXTERNAL LINE OF SAID PREDETERMINED CHARACTERISTIC ADMITTANCE.